RAM:
https://www.jameco.com/z/HM62256LP-70-Major-Brands-IC-62256LP-70-Low-Power-CMOS-SRAM-256K-Bit-32Kx8-70ns_82472.html

UART:
https://www.jameco.com/z/PC16550DN-Major-Brands-Universal-Asynchronous-Receiver-Transmitter-with-FIFOs-DIP-40_27596.html

Not available on Jameco: HD63C09, 28C256, uPD72020, VT82C42, 74LS612.
eBay may be a better choice.